At a glance

What is human chorionic gonadotropin?

Human chorionic gonadotropin, abbreviated hCG, is a glycoprotein hormone normally produced by the placenta in pregnancy. The FDA-approved injectable products, such as Pregnyl and Novarel, are purified from the urine of pregnant women; a separate recombinant version, choriogonadotropin alfa (Ovidrel), is made in the laboratory. hCG shares its structure and action closely with luteinizing hormone, one of the pituitary hormones that controls the ovaries and testes.

How does human chorionic gonadotropin work?

hCG binds the same receptor as luteinizing hormone (the LH/CG receptor) and mimics the natural mid-cycle luteinizing hormone surge. In women undergoing fertility treatment, a dose of hCG triggers the final maturation and release of the egg after the follicles have been grown with other hormones. In men, hCG stimulates the Leydig cells of the testes to produce testosterone and supports sperm production, which is why it is used in hypogonadotropic hypogonadism. In boys with non-anatomical undescended testicles, the testosterone it stimulates can promote testicular descent.

In a Cochrane review, urinary-derived and recombinant hCG gave similar ongoing pregnancy or live-birth rates¹ for triggering final egg maturation (odds ratio 1.15, 95% CI 0.89 to 1.49; seven trials, 1,136 women). The FDA has specifically stated that hCG has not been shown² to be effective for weight loss and is not approved for that use, despite its promotion in some commercial diet programs.

Is it FDA-approved?

Yes, for its hormonal indications. The injectable hCG products have been FDA-approved³ for decades for ovulation induction, male hypogonadism, and cryptorchidism. The agency has separately warned that over-the-counter "homeopathic" hCG weight-loss products are not approved and that prescription hCG is not approved for weight loss.

What is human chorionic gonadotropin prescribed for?

In women, hCG is prescribed to induce ovulation and pregnancy in carefully selected cases of infertility, after the follicles have been developed with follicle-stimulating hormone or menotropins. In men, it is used for hypogonadotropic hypogonadism, and in prepubertal boys for undescended testicles not caused by an anatomical blockage.

Evidence in men comes from small or short studies, summarized below:

What are the side effects?

According to the prescribing information³, common side effects include:

• Injection-site pain
• Headache
• Fluid retention or edema
• Breast tenderness or gynecomastia (in males)
• Irritability, restlessness, and depression

More serious considerations include:

• Ovarian hyperstimulation syndrome and multiple pregnancy in fertility use
• Signs of early puberty in boys treated for cryptorchidism
• Rare arterial thromboembolism

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